CVE-2026-9390: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-mhmm-7px6-jx3j
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CVSS 9.1
CWE-643
Published
Advisory Summary

CVE-2026-9390 is a CRITICAL (CVSS 9.1) security vulnerability vulnerability (CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection')) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product uses external input to dynamically construct an xpath expression used to retrieve data from an xml database, but it does not neutralize or incorrectly neutralizes that input. this allows an attacker to control the structure of the query.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-9390 at a Glance

CVE Identifier CVE-2026-9390
GHSA Identifier GHSA-mhmm-7px6-jx3j
Severity CRITICAL
CVSS v3.1 Base Score 9.1
CWE Classification CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection')
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability None (A:N)

How to Fix CVE-2026-9390

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-9390, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection'), where the product uses external input to dynamically construct an xpath expression used to retrieve data from an xml database, but it does not neutralize or incorrectly neutralizes that input. this allows an attacker to control the structure of the query. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup. verify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators. A crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference.

References

NVD — CVE-2026-9390 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-9390
Security Fix Commit FIX COMMIT
https://github.com/perl-net-saml2/perl-XML-Sig/commit/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch
Security Fix Commit FIX COMMIT
https://github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch
metacpan.org/release/timlegge/xm... WEB
https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/changes

Frequently Asked Questions

What is CVE-2026-9390?
CVE-2026-9390 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection').
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-9390?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-9390?
CVE-2026-9390 has a CVSS v3.1 base score of 9.1 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-9390?
CVE-2026-9390 is classified under CWE-643: Improper Neutralization of Data within XPath Expressions ('XPath Injection') (The product uses external input to dynamically construct an XPath expression used to retrieve data from an XML database, but it does not neutralize or incorrectly neutralizes that input. This allows an attacker to control the structure of the query.).
How can I check Maven dependencies for CVE-2026-9390?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-mhmm-7px6-jx3j",
  "modified" : "2026-08-03T21:31:35Z",
  "published" : "2026-08-03T15:32:49Z",
  "aliases" : [ "CVE-2026-9390" ],
  "details" : "XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup.\n\nverify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators.\n\nA crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-9390"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/perl-net-saml2/perl-XML-Sig/commit/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch"
  }, {
    "type" : "WEB",
    "url" : "https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/changes"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-643" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-03T14:16:30Z"
  }
}